An internal combustion engine is generally powered by energy which is generated when a mixed gas is combusted in a combustion chamber. Here, the mixed gas includes air and a fuel. An intake passage, through which the mixed gas or air to be mixed with a fuel is supplied, is connected to a cylinder of the engine.
In recent years, research on guiding a swirl flow by controlling the amount of intake air of at least one of two intake air passages in a state where the two intake air passages are connected to one cylinder and development of an apparatus for the same have been developed.
The swirl represents a vortex phenomenon occurring in the combustion chamber during the intake of the mixed gas or air, and when swirl with a predetermined magnitude occurs, an ignition state may be enhanced and combustion efficiency may be improved.
However, in a case where a configuration of an apparatus for guiding the swirl flow is complicated, manufacturing cost and weight increase, and fuel efficiency decreases.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.